There are a lot more hurdles to making a proper thermo-nuclear bomb. Implosion type bombs which form the initial boost of Teller-Ulam designs are much more comp

There are a lot more hurdles to making a proper thermo-nuclear bomb. Implosion type bombs which form the initial boost of Teller-Ulam designs are much more complex to implement because the explosive shell needs to be set off simultaneously so that it properly crushes the fissile material.